I'm too damn tall for smith calf raises, so for me it's useless. I did use it for a little while after I tore my intercoastal. Seemed to be good at working my chest/shoulders/tri's without bothering my injury much. But for the price it might cost to fix it, I would toss it and get a free weight bench and rack.
As other's put, the smith is bs. It gives you a false feeling of strength. When I was healed and did go back to free weight bench, I was so shaky. All the little stabilizer muscles that we don't even think about get ignored on a smith.